Rare Hemispiticeras Ammonite Fossil, Tithonian Stage Late Jurassic, Authentic Madagascar Collectors Piece with Certificate of Authenticity

Description

Authentic Jurassic Ammonite Fossil

This listing presents a genuine Hemispiticeras Ammonite Fossil from the Tithonian Stage of the Late Jurassic, discovered in Madagascar. Ammonites were extinct marine molluscs belonging to the subclass Ammonoidea, closely related to squid and cuttlefish. Their beautifully coiled shells, divided into chambers, are among the most iconic fossils, treasured both for their natural beauty and their scientific importance. The photographs show the exact specimen offered, with a 1 cm scale cube included for accurate measurement.

Geological Context – Tithonian, Jurassic

The Tithonian Stage, dated to around 152–145 million years ago, marks the closing stage of the Jurassic period, just before the beginning of the Cretaceous. During this time, Madagascar was part of the southern supercontinent Gondwana, positioned in a warm tropical marine environment. These seas teemed with marine life, and conditions of sedimentation in these shallow waters allowed ammonite shells to be buried quickly and fossilised in remarkable detail.

Ammonites from this interval are especially important in stratigraphy as index fossils, because their rapid evolutionary cycles and wide distribution allow geologists to date and correlate Jurassic deposits with precision. Fossils of Hemispiticeras are therefore of both scientific and collector’s significance.

Species Profile – Hemispiticeras

The genus Hemispiticeras belongs to the family Olcostephanidae, within the superfamily Perisphinctoidea and order Ammonitida. It is a characteristic genus of the Late Jurassic ammonite fauna, with features that make it distinctive among ammonites from the Tithonian Stage.

Notable features of Hemispiticeras include:

• A moderately evolute shell with visible earlier whorls.
• Strong ribbing, often bifurcating as it crosses the flanks toward the venter.
• A rounded venter, typically without a sharp keel, giving the shell a robust appearance.
• A relatively wide umbilicus, allowing inner coils to be easily observed.
• Complex suture lines marking chamber separations, highlighting the genus’ intricate internal shell structure.

These features give Hemispiticeras its distinct visual character, making it easily recognisable and an important fossil for paleontologists and collectors alike.

Paleoenvironment and Scientific Importance

During the Late Jurassic, Madagascar was positioned within the Tethys Ocean region, surrounded by shallow tropical seas. Ammonites such as Hemispiticeras lived as nektonic predators, swimming actively and preying on smaller invertebrates. When they died, their shells sank and were quickly buried in fine sediments, which allowed for exceptional preservation over millions of years.

The presence of Hemispiticeras in Madagascar deposits is particularly significant for paleontology, as it provides insights into the diversity and distribution of ammonites across Gondwana during the Jurassic. Its restricted stratigraphic range also makes it a useful fossil for correlating Tithonian deposits across different regions of the southern hemisphere.

100% Genuine with Certificate of Authenticity

All of our fossils are guaranteed 100% genuine specimens and come complete with a Certificate of Authenticity. This ammonite is not a cast or reproduction but an authentic relic of Jurassic seas, preserved for more than 150 million years.

A Collector’s and Display Fossil

This Hemispiticeras ammonite fossil from the Tithonian of Madagascar is an excellent specimen for collectors, educators, and natural history enthusiasts. Its striking ribbing, geological provenance, and scientific importance make it a beautiful and historically meaningful fossil for any collection or display.

Scale Rule Squares / Cube = 1 cm. Please see listing photos for the full sizing of this exact specimen.